This CL includes the following fixes:
* Fix for incorrect non-nullable assumption about _Closure._hash field.
* Add error handling into BecomeMapTraits::Hash.
* Correct assertions for validating layout of Closure objects.
* Add identityHashCode to the list of VM entry points in precompiler.
Closes#30211.
Original code review:
https://codereview.chromium.org/2983823002/
Original CL description:
This performance improvement is inspired by Flutter listeners stored in
the HashSet (see ObserverList) and frequently checked using
HashSet.contains(). If there are many such listeners and they are
implicit instance closures (for example, created by
'new Listenable.merge(...)'), HashSet.contains() becomes very slow.
It spends a lot of time in Closure_equals native method due to hash
collisions between closure objects with same function
but different receivers.
This CL improves hashCode() calculation for implicit instance closures
by mixing function hashcode with identity hashcode of the receiver.
For explicit closures and static implicit closures hashCode() is
improved by using identityHashCode() of a closure object.
Also, hashcode is calculated once and cached in each closure instance.
The size of a closure instance doesn't grow up because there was unused
word-size padding both on 32-bit and 64-bit architectures.
The execution time of the following micro-benchmark is reduced from
47665ms to 135ms on my Linux/x64 box.
-------------------------------------
import "dart:collection";
class Foo {
int _a;
Foo(this._a);
void bar() {}
}
main() {
HashSet hs = new HashSet();
for (int i = 0; i < 1000; ++i) {
hs.add(new Foo(i).bar);
}
var watch = new Stopwatch()..start();
for (int i = 0; i < 1000; ++i) {
for (var c in hs) {
hs.contains(c);
}
}
int time = watch.elapsedMilliseconds;
print("Time: ${time}ms\n");
}
-------------------------------------
R=zra@google.com
Review-Url: https://codereview.chromium.org/2988493002 .
This performance improvement is inspired by Flutter listeners stored in
the HashSet (see ObserverList) and frequently checked using
HashSet.contains(). If there are many such listeners and they are
implicit instance closures (for example, created by
'new Listenable.merge(...)'), HashSet.contains() becomes very slow.
It spends a lot of time in Closure_equals native method due to hash
collisions between closure objects with same function
but different receivers.
This CL improves hashCode() calculation for implicit instance closures
by mixing function hashcode with identity hashcode of the receiver.
For explicit closures and static implicit closures hashCode() is
improved by using identityHashCode() of a closure object.
Also, hashcode is calculated once and cached in each closure instance.
The size of a closure instance doesn't grow up because there was unused
word-size padding both on 32-bit and 64-bit architectures.
The execution time of the following micro-benchmark is reduced from
47665ms to 135ms on my Linux/x64 box.
-------------------------------------
import "dart:collection";
class Foo {
int _a;
Foo(this._a);
void bar() {}
}
main() {
HashSet hs = new HashSet();
for (int i = 0; i < 1000; ++i) {
hs.add(new Foo(i).bar);
}
var watch = new Stopwatch()..start();
for (int i = 0; i < 1000; ++i) {
for (var c in hs) {
hs.contains(c);
}
}
int time = watch.elapsedMilliseconds;
print("Time: ${time}ms\n");
}
-------------------------------------
R=rmacnak@google.com, zra@google.com
Review-Url: https://codereview.chromium.org/2983823002 .
Add function_type_arguments field in closure instances.
Lots of other smaller changes, also related to generic function semantics.
This is still work in progress, with a change of direction in the design:
The type argument vector of a generic function will be prepended with the type
arguments of enclosing generic functions. The re-allocation and concatenation
will be done in nested generic function's prolog. This will greatly simplify
instantiation of types at run time without having to search the context for
parent function's type arguments. However, a closure instance now requires an
additional field. On the other hand, type parameters do not require a
parent_level field anymore.
R=rmacnak@google.com
Review-Url: https://codereview.chromium.org/2818273002 .
They were used as the class of closure instances and as the type class of
function types.
All closure instances now have class _Closure and function types are represented
by a new class FunctionType extending AbstractType.
Fix issue 24567 and add regression test.
R=asiva@google.com, rmacnak@google.com
Review URL: https://codereview.chromium.org/1584223006 .
By inserting the necessary checks for null inside the callee
at the AST level, the code generation of == operations can be
greatly simplified.
This is a performance-neutral change and a step for allowing
generic inlining of arbitrary == methods. So far we could only
inline them for a common set of types in the flow graph
optimizer.
R=srdjan@google.com
Review URL: https://codereview.chromium.org//24203004
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@28084 260f80e4-7a28-3924-810f-c04153c831b5
Alexander Markov